Myriolecis semipallida
Nomenclature
-
Family: LecanoraceaeGenus: Myriolecis
SUMMARY
|
Thallus endolithic, grey to blackened, strongly contrasting in colour with the apothecium margin. Apothecia 0.5-1.4 mm diam., widely dispersed to partly crowded, sessile to constricted, margin 0.05-0.15 µm thick, white or faintly yellow, sometimes with a blue pigment, smooth, farinose or slightly crenulate; disc pale to grey-brown, not or slightly pruinose; epithecium granular K–, N–, pigment dissolving, without crystals; paraphyses as in L. albescens. Thallus C–, K–, Pd–, UV–; apothecium margin C± yellow, K+ yellow, KC+ yellow, Pd–, UV+ yellow or bright orange (vinetorin). On calcareous rocks, especially hard limestone. Common and widespread in Britain and Ireland, but not distinguished until recently. Specimens with a yellow colour on the thalline margin and the UV+ orange rather than bright yellow reaction were previously referred to Lecanora xanthostoma. Often confused with Myriolecis dispersa which differs in the absence of a UV reaction, the white, never black, thallus and the more crowded, never blued apothecia. See also M. crenulata. Description adapted from Edwards et al. (2009). Map © BLS. |
 |